Tripper system



P 1956 o H. SCHMITT 2,762,263

TRIPPER SYSTEM Filed July 51, 1944 TO BOMB RELEASE DEVICE INVENTOR OTTO H. SGHM/TT ATTORNEYS Unite- States This invention relates to automatic release systems,

and more particularly to systems adapted to cause the release ofv missiles in responseto. a desired portion of a signal caused by a magnetic anomaly.

Magnetometers are*well known which are capable of producing.v an output. signal. in .response to magnetic anomalies, as for examplethosedue tothe presence-of a submarine or other. large. magnetic. bodies in the proximity of the magnetometer- Whensuch magnetometers are used in the detection anddestruction of? submarines, tliey=are mounted upon a carrier, as for example an aircraft, and the latter. is maneuvered in the region where the presence of a submarine is suspected. The indications secured with the aid of the magnetometer vary in accordance with a number of factors, including the magnetic moment and heading of the submarine, the altitude and heading of the aircraft, and the characteristics of the magnetometer itself.

An object of this invention is the provision of means for releasing missiles in response to magnetic anomalies, release being caused either by the inflection point or by the peak point of the signal, depending upon the choice of time constants of the circuit.

It is an object of the present invention to utilize such magnetometer signals for the purpose of automatically releasing missiles, as for example bombs, when the carrier is at "a point substantially directly above the submarine. Depending upon the time delay inherent in the magnetometer system from which the system of the invention derives its signal and upon whether or not the missilereleasing device to be actuated by the system of the invention is of the retroactive type, release is preferably accomplished at different portions of the magnetic anomaly. The two principal distinctive points for signals of most shapes are the peak point and the point of inflection. In some cases, therefore, it may be desirable to accomplish release after the signal reaches its peak value. Operation in this manner is especially useful where the magnetometer system has a relatively short time delay or where a retroactive bomb-release device is employed. In other cases, especially in those in which the magnetometer system has a relatively long time delay or when it is desired to dispense with the use of a retroactive bombrelease device, release near the first inflection point of the signal is preferable. In the arrangement in accordance with the present invention, means are provided for securing release by either the peak point or the inflection point of the signal, this choice of mode of operation being made merely by throwing a single switch.

Referring now to the drawing (which illustrates a preferred embodiment), the balanced output signal from the magnetometer system, not shown, is applied to input terminals 11 and 12 across grid leak resistors 13 and 14 to the grids of triodes 16 and 17. Triodes 16 and 17 are arranged in push-pull with plate resistors 18 and 19, respectively, and common cathode resistor 21, so that the potential of one plate goes positive when that of the other goes negative. Assuming for the moment that switch 22 is closed and hence set for release at the inflection point and that the plate of tube 16 is shifting in a negative direction, current flows through diode 23, thus releasing part of the charge on capacitor 24. At the same time, however, the plate of tube 17 is becoming more positive,

atent 2,762,263 Patented Sept. 11, 19.5.6

so that diode 26 passes-nocurrent. Hence, through the agency of capacitor 27 the plate voltage variationdif ferentiated across load resistor 28 shunted by resistor 29, and a positive signal, proportional inmagnitude to the firstderi'vative of the input signal, is conducted through trol grid exceeds this cutoff value, plate current flows through plate resistor 35 and the platefvol'tage swings. This. negative swing causes capacitor-37, to. discharge through diode 381 As soon as the. negative. swing stops and the variation becomes positive,.- dij. 38 becomes nonconductive, and capacitor 37" qt lickly' builds up a positive potential. with respect to ground across. resistor "39. The inflec'tion-point'voltage thus developed' negative.

across resistor 39 is used to render thyratron 41 conductive, this tube previously having been maintained nonconductive by bias cells 42 in its control-grid circuit. The voltage developed across resistor 43 in the thyratron cathode circuit is utilized to actuate any suitable bomb-release device. Reset is accomplished by opening and closing switch 44, which is normally closed.

It will be understood that the first derivative of the signal represents its slope, and that the second derivative is the rate of change of this slope with time. When this second derivative is equal to zero, the rate of change of slope of the input signal is zero, and this is the point of inflection. In other words, this is the point at which the slope, which previously had been increasing, stops increasing and begins to decrease. It will be apparent that it is unimportant whether the input signal at terminals 11 and 12 is positive or negative at a given instant, since the system converts a signal of either polarity into positive swings before taking the first and second derivatives.

To secure operation as a peak tripper, switch 22 is opened, thus removing resistors 29 and 34, previously in shunt with load resistors 28 and 33, respectively. This increases the resistance effectively in series with each of capacitors 24 and 27, thereby increasing the time constant of their discharge circuits, and effectively making this stage an amplifier rather than a dilferentiator. The remainder of the circuit functions as described above in connection with operation as an inflection tripper.

Although it is apparent that there are many suitable values for the components and quantities shown and indicated in the drawing, the following listing of values for the most significant components and quantities is presented for illustrative purposes:

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a control circuit for releasing a bomb in response to the presence of a magnetic anomaly detected by a magnetometer or other like system, and having a release mechanism controlled by an impulse from said circuit, means for receiving the output signal from said system, a small time constant network for producing a signal proportional to the second derivative of said received signal, and means selectively responsive to the reduction to zero of the second derivative of said received signal for producing said impulse whereby release of the bomb may magnetometer or other like system, and having a release mechanism controlled by an impulse from said circuit, means for receiving the output signal from said system, a long time constant network for producing a signal proportional to the first derivative of said received signal, and means selectively responsive to the reduction to zero of the first derivative of said received signal for producing said impulse, whereby release of the bomb may be obtained.

4. A combination as defined in claim 3, wherein said responsive means further includes a thyratron for delivering said impulse in response to reduction of said produced signal to zero, and a normally closed reset switch in th plate circuit of said thyratron.

References Cited in the file of this patent UNITED STATES PATENTS 2,233,415 Hall Mar. 4, 1941 2,406,870 Vacquier Sept. 3, 1946 2,408,078 Labin Sept. 24, 1946 2,448,718 Konlicovitch Sept. 7, 1948 2,483,417 Johnson Oct. 4, 1949 

